Chromatography Forum

In a method we are currently working on, we find that we get some tailing of our BHT peak. I find this to be quite surprising.

BHT is a benzene ring, with 2 tert-butyl groups, and an OH group. You really wouldn't expect much tailing from this molecule.

Our mobile phase is 0.1% formic acid in a water/acetonitrile gradient. And we are using a phenyl column (if that has any significance).

Has anyone else experiences this? Any thoughts?

Is it possible something is co-eluting at the tail end of the peak?

Are other peaks in the chromatogram also tailed? Can you check a test mix?

If all are tailed, perhaps you have a column problem - blocked frit, void, bad connection.

If only BHT is tailing, then you may have an impurity, as Bryan suggested.

I've only run BHT on a C18 column, but mostly I'd use capillary GC for it. With HPLC, since the phenolic group is so hindered, you likely don't even need the acid modifier, but it shouldn't hurt. Can you try on C18?